Implement InputTakeAtPosition for Span

Author: subhojit777

source/tokens.rs

@@ -51,6 +51,12 @@ use nom::{
     InputIter,
     InputLength,
     InputTake,
+    InputTakeAtPosition,
+    IResult,
+    Err,
+    Needed,
+    Context,
+    ErrorKind,
     Offset,
     Slice
 };
@@ -825,6 +831,51 @@ pub struct Span<'a> {
     slice: Input<'a>
 }
 
+impl<'a> InputTakeAtPosition for Span<'a> {
+  type Item = InputElement;
+
+  fn split_at_position<P>(&self, predicate: P) -> IResult<Self, Self, u32>
+  where
+    P: Fn(Self::Item) -> bool,
+  {
+    match (0..self.slice.len()).find(|b| predicate(self.slice[*b])) {
+      Some(i) => Ok((Span {
+          offset: self.offset,
+          line: self.line,
+          column: self.column,
+          slice: &self.slice[i..],
+      }, Span {
+          offset: self.offset,
+          line: self.line,
+          column: self.column,
+          slice: &self.slice[..i],
+      })),
+      None => Err(Err::Incomplete(Needed::Size(1))),
+    }
+  }
+
+  fn split_at_position1<P>(&self, predicate: P, e: ErrorKind<u32>) -> IResult<Self, Self, u32>
+  where
+    P: Fn(Self::Item) -> bool,
+  {
+    match (0..self.slice.len()).find(|b| predicate(self.slice[*b])) {
+      Some(0) => Err(Err::Error(Context::Code(*self, e))),
+      Some(i) => Ok((Span {
+          offset: self.offset,
+          line: self.line,
+          column: self.column,
+          slice: &self.slice[i..],
+      }, Span {
+          offset: self.offset,
+          line: self.line,
+          column: self.column,
+          slice: &self.slice[..i],
+      })),
+      None => Err(Err::Incomplete(Needed::Size(1))),
+    }
+  }
+}
+
 impl<'a> InputTake for Span<'a> {
     fn take(&self, count: usize) -> Self {
         Span {